package thread;

import static java.lang.Thread.sleep;

class MyBlockingQueue {
    private String[] elems = null;
    private int head = 0;
    private int tail = 0;
    private int size = 0;
    Object locker = new Object();

    public MyBlockingQueue(int capacity) {
        elems = new String[capacity];
    }

    public void put(String elem) throws InterruptedException {
        synchronized (locker) {
            while(size >= elem.length()) {
                //队列满了就阻塞
                locker.wait();
            }

            elems[tail] = elem;
            tail++;
            if(tail >= elems.length) {
                tail = 0;
            }
            size++;

            // 入队列成功后唤醒
            locker.notify();
        }
    }

    public String take() throws InterruptedException {
        String elem = null;
        synchronized (locker) {
            while(size == 0) {
                // 队列空了
                // 也需要这个代码阻塞
                locker.wait();
            }

            elem = elems[head];
            head++;
            if(head >= elems.length) {
                head = 0;
            }
            size--;

            //元素出队列成功后, 唤醒
            locker.notify();
        }

        return elem;
    }
}

public class ThreadDeom29 {
    public static void main(String[] args) {
        MyBlockingQueue queue = new MyBlockingQueue(1000);
        //生产者
        Thread t1 = new Thread(()->{
            int n = 1;
            while(true) {
                try {
                    queue.put(n + "");
                    System.out.println("生产元素 " + n);
                    sleep(1000);
                    n++;
                } catch (InterruptedException e) {
                    throw new RuntimeException(e);
                }
            }
        });

        //消费者
        Thread t2 = new Thread(()-> {
            while(true) {
                try {
                    String n = queue.take();
                    System.out.println("消费元素 " + n);
                } catch (InterruptedException e) {
                    throw new RuntimeException(e);
                }
            }
        });

        t1.start();
        t2.start();
    }
}
